Precise separation of complex mixtures is of great significance. Membrane technology is attractive for advanced molecular separation due to its energy efficiency and environmental friendliness. ...Herein, charged membranes with β-cyclodextrin (CD) scaffolds are prepared for precise sieving of complex molecular mixtures. Interfacial polymerization between trimesoyl trichloride and CD-based zwitterions could generate a selective separation layer composed of the CD-scaffolded porous network and plentiful quaternary ammonium groups. Both hydrophilic and hydrophobic channels existing in the separation layer endow the membrane with high permeance of polar and nonpolar solvents. The sieving mechanism of the CD-based membrane is investigated, demonstrating that the Donnan effect and size exclusion have different influences on anionic, cationic and neutral molecules during filtration. The size- and charge-dependent molecular sieving is determined by the inner cavities of CDs, outer spaces between CDs and the quaternary ammonium groups of the cross-linked CD network. This charged CD-based membrane can stably and precisely discriminate molecules with different charges, molecular weights or shapes.
The charged CD-based membrane can precisely discriminate molecules with different charges, molecular weights, or shapes, which was determined by the inner cavities of CDs, outer spaces between CDs, and quaternary ammonium groups of the CD network.
Objective. The design of the stimulation paradigm plays an important role in steady-state visual evoked potential (SSVEP)-based brain-computer interface (BCI) studies. Among various stimulation ...designs, the dual-frequency paradigm in which two frequencies are used to encode one target is of importance and interest. However, because the number of possible frequency combinations is huge, the existing dual-frequency modulation paradigms failed to optimize the encoding towards the best combinations. Thus, this work aiming at designing a new dual-frequency and phase modulation paradigm with the best combinations stimuli. Approach. This study proposed a dual-frequency and phase modulation method, which can achieve a large number of targets by making different combinations of two frequencies and an initial phase. This study also designed a set of methods for quickly optimizing the stimulation codes for the dual-frequency and phase modulation method. Main results. An online 40-class BCI experiment with 12 subjects obtained an accuracy of 96.06 ±4.00% and an averaged information transfer rate (ITR) of 196.09 ±15.25 bits min−1, which were much higher than the existing dual-frequency modulation paradigms. Moreover, an offline simulation with a public dataset showed that the optimization method was also effective for optimizing the single-frequency and phase modulation paradigm. Significance. These results demonstrate the high performance of the proposed dual-frequency and phase modulation method and the high efficiency of the optimization method for designing SSVEP stimulation paradigms. In addition, the coding efficiency of the optimized dual-frequency and phase modulation paradigm is higher than that of the single-frequency and phase modulation paradigm, and it is expected to further realize the BCI paradigm with a large amount of targets.
Abstract
Objective.
Achieving high precision rapid serial visual presentation (RSVP) task often requires many electrode channels to obtain more information. However, the more channels may contain ...more redundant information and also lead to its limited practical applications. Therefore, it is necessary to reduce the number of channels to enhance the classification performance and users experience. Furthermore, cross-subject generalization has always been one of major challenges in electroencephalography channel reduction, especially in the RSVP paradigm. Most search-based channel selection method presented in the literature are single-objective methods, the classification accuracy (ACC) is usually chosen as the only criterion.
Approach.
In this article, the idea of multi-objective optimization was introduced into the RSVP channel selection to minimize two objectives: classification error and the number of channels. By combining a multi-objective evolutionary algorithm for solving large-scale sparse problems and hierarchical discriminant component analysis (HDCA), a novel channel selection method for RSVP was proposed. After that, the cross-subject generalization validation through the proposed channel selection method.
Main results.
The proposed method achieved an average ACC of 95.41% in a public dataset, which is 3.49% higher than HDCA. The ACC was increased by 2.73% and 2.52%, respectively. Besides, the cross-subject generalization models in channel selection, namely special-16 and special-32, on untrained subjects show that the classification performance is better than the Hoffmann empirical channels.
Significance.
The proposed channel selection method could reduce the calibration time in the experimental preparation phase and obtain a better accuracy, which is promising application in the RSVP scenario that requires low-density electrodes.
Potassium-ion energy-storage devices have established themselves as the most important candidates for next-generation energy-storage devices in the coming future. Recently, inorganic electrode ...materials have riveted ever-increasing interest due to large theoretical capacity, rich sources, low price and environmental friendly advantages. However, the electrode materials of potassium-containing devices have been suffering low theoretical capacity, poor rate performance and short lifespan due to integration effects of seriously electrochemical pulverization and slow kinetics. In this timely review, we will focus on the latest progress of potassium ion energy storage devices based on beyond-carbon materials, referring to the synthesis of materials and the construction of microstructure, material component-oriented electrochemical performance, energy storage mechanism discussion, newfangled device assembly and key components. The key materials and novel theories are reviewed, and some personal viewpoints have been proposed, targeting providing some inductive opinions.
Potassium-ion energy-storage devices have established themselves as one of the most important candidates for next-generation energy-storage devices in the coming future. In this timely review, we will focus on the latest progress of key materials and novel theories in potassium-containing devices. And some personal viewpoints have been proposed, targeting providing some inductive opinions. Display omitted
•The beyond-carbon anode materials for potassium ion batteries were systematically analyzed and summarized.•Other components of potassium ion batteries, such as cathode, electrolyte and binder, were also studied.•The development bottleneck of potassium ion battery was analyzed and some countermeasures were put forward.•It provides comprehensive and reliable information and enlightening opinions for the researchers of new energy devices.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Existing urban street planning often neglects human perception despite being designed for human utility. Therefore, exploring the relationship between urban street planning and human perception, ...especially restorative perception, is crucial for sustainable urban planning. In this study, we analyzed restorative perception of urban streets among different population groups and accessibility of urban streets using Baidu Street View Images, deep learning, and space syntax. Furthermore, we clarified the impacts of various street elements on restorative perception using correlation and ridge regression analyses. Based on restorative perception and accessibility coupling assessment, streets were classified into four types, identifying “inefficient segments” and “prioritized segments”. The results showed that: 1) the level of restorative perception of streets in Nanjing was relatively limited and exhibited variation across different population groups; 2) the impacts of different street elements on restorative perception varied, with trees having the highest positive impact (β = 0.378), while walls had the greatest negative impact (β = − 0.182); and 3) “prioritized segments” and “inefficient segments” represented 33.92 % and 17.96 %, respectively, indicating the urgent demand for streets planning and renewal. These findings can offer targeted recommendations for enhancing restorative environment of urban streets and identifying priority areas for urban street planning.
•Restorative perception of streets varies among different population groups.•Trees had the most positive influence on restorative perception, while walls exhibited the largest negative impact.•Identifying "prioritized segments" and "inefficient segments" can provide targeted suggestions for urban street planning.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Current ear electrodes often require complex placing or long stimulation durations to achieve good detection of steady-state visual evoked potential (SSVEP). To improve the practicability of ear ...electrode-based SSVEP-BCI (brain-computer interface) system, we developed a high-performance ear electrode that can be easily placed.
Hydrogel based disposable and replaceable semi-dry electrodes are developed to improve the contact impedance and wear feeling. The best combination of electrodes for SSVEP-BCI application around the ear is optimized by assessing the electrode on volunteers, and the performance of the electrode was compared with that of the occipital electrode.
The developed ear hydrogel electrode can achieve an impedance close to that of the wet electrode. Three combinations of ear electrode groups demonstrate high information transfer rate (ITR) and accuracy in SSVEP-BCI applications. According to the rating of the comprehensive assessment and BCI performance in the online session, the behind-aural electrode is the best electrode combination for recording SSVEP in the ear region. The average preparation time is the shortest, and the average impedance is the lowest. The ITR of the behind-aural electrode based SSVEP-BCI system can reach 37.5 ± 18 bits min
. The stimulus duration was as low as 3 s compared to 5 s or 10 s in other studies.
The accuracy, ITR, and wear feeling can be improved by introducing a semi-dry ear electrode and optimizing the position and the combination of ear electrode. By providing a better trade-off between performance and convenience, the ear electrode-based SSVEP-BCI promises to be used in daily life.
Abstract
Objective
. Steady-state visual evoked potential (SSVEP) based brain–computer interfaces (BCIs) often struggle to balance user experience and system performance. To address this challenge, ...this study employed stimuli in the 55–62.8 Hz frequency range to implement a 40-target BCI speller that offered both high-performance and user-friendliness.
Approach
. This study proposed a method that presents stable multi-target stimuli on a monitor with a 360 Hz refresh rate. Real-time generation of stimulus matrix and stimulus rendering was used to ensure stable presentation while reducing the computational load. The 40 targets were encoded using the joint frequency and phase modulation method, offline and online BCI experiments were conducted on 16 subjects using the task discriminant component analysis algorithm for feature extraction and classification.
Main results
. The online BCI system achieved an average accuracy of 88.87% ± 3.05% and an information transfer rate of 51.83 ± 2.77 bits min
−1
under the low flickering perception condition.
Significance
. These findings suggest the feasibility and significant practical value of the proposed high-frequency SSVEP BCI system in advancing the visual BCI technology.
Green tea polyphenol epigallocatechin-3-gallate (EGCG) may help prevent metabolic syndrome and nonalcoholic fatty liver disease (NAFLD). However, the underlying mechanisms of its protective effects ...are complicated and remain unclear. With the gut-liver axis theory as a foundation, the present study investigated the effects of EGCG on intestinal mucosal immunity in male C57BL/6 mice fed a high-fat Western diet or the diet supplemented with 0.4% dietary EGCG (w/w) for 14 weeks. Dietary EGCG supplementation effectively prevented changes-including excessive accumulation of visceral and hepatic fat, abnormal liver function, and elevated concentrations of serum and liver inflammatory cytokines-known to be caused by high-fat diets. In addition, serum lipopolysaccharide concentrations decreased by 94.3%. RNA sequencing data of differentially expressed genes in ileal samples among three groups indicated that most of the pathways in the Kyoto Encyclopedia of Genes and Genomes in the first 20 enrichment levels were related to immunity and inflammatory reactions. Real-time reverse transcription quantitative polymerase chain reaction was used to determine alterations in expression levels of key genes related to intestinal immune function and inflammatory responses from ileal and colonic samples. Changes in secretory immunoglobulin A in the small intestine, serum, and feces further demonstrated improved intestinal mucosal immunity in the EGCG-treated mice. In conclusion, dietary EGCG effectively prevented the development of NAFLD and significantly improved intestinal mucosal immunity in mice with obesity induced by a high-fat diet. However, whether improved intestinal immune function is the key mechanism underlying the health benefits of dietary EGCG warrants further research.
Dietary EGCG maintains the intestinal immune homeostasis, which might play a role in preventing systemic inflammation and NAFLD.
The existing multi-satellite dynamic mission planning system hardly satisfies the requirements of fast response time and high mission benefit in highly dynamic situations. In the meantime, a ...reasonable decision-maker preference mechanism is an additional challenge for multi-satellite imaging dynamic mission planning based on user preferences (MSDMPUP). Therefore, this study proposes the hybrid preference interaction mechanism and knowledge transfer strategy for the multi-objective evolutionary algorithm (HPIM–KTSMOEA). Firstly, an MSDMPUP model based on a task rolling window is constructed to achieve timely updating of the target task importance degree through the simultaneous application of periodic triggering and event triggering methods. Secondly, the hybrid preference interaction mechanism is constructed to plan according to the satellite controller’s preference-based commands in different phases of the optimal search of the mission planning scheme to effectively respond to the dynamic changes in the environment. Finally, a knowledge transfer strategy for the multi-objective evolutionary algorithm is proposed to accelerate population convergence in new environments based on knowledge transfer according to environmental variability. Simulation experiments verify the effectiveness and stability of the method in processing MSDMPUP. This study found that the HPIM–KTSMOEA algorithm has high task benefit, short response time, and high task completion when processing MSDMPUP.
